metzgar



Jan.

1927 C. W. METZGAR COMPRESSOR UNLOADER 2 Sheets-Sheet 1 INVENTOR I wlifififem $5 I Hes ATTRNEY.

Filed NOV. 5

Jan 4, 1927. 2,933"

' c. W. METZGAR COMPRESSOR UNLOADER Filed Nov. 5, 1925 2 Sheets-Sheet 2 H 0 5 ATTOW iii) Patented Jan; 4, 1927.

res

UNITED CHESTER W. ME'IZGAB, OF EASTON, PENNSYLVANIA, ASSIGNOR TO INGEBSOLL-RANID COMPANY, OF JERSEY CITY, NEXV JERSEY, A CORPORATION OF NEW JERSEY.

COMPRESSQR UNLOADER.

Application filed November This invention relates to compressor unloaders, but more particularly to a regulator for unloading and loading a compressor step by step.

The invention is in some respects an unprovement upon the device disclosed in U. S. Patent No. 1,430,578, granted to me October 3, 1922, for a compressor regulator, in which the clearance valves are held closed by receiver pressure and assisted in openlng by springs when the receiver pressure is released.

In the present invention substantially the reverse of this is true, since I have devised means for opening the clearance valves by the application of receiver pressure, and depend uponother means, such as springs, for closing the valves.

The usual type of clearance regulator is not conveniently applicable for the purposes of the present invention, and my object is primarily to secure a simple and eiiicient regulator by means of which the valves which unload the compressor may be positively opened and held open by receiver pres sure. The regulator has a wide application and is not confined to clearance control, but may be used in cases in which the unloading steps are effected by other than clearance chambers and valves, as will be readily ap parent to those skilled in the art, and the unloader may be applied to single or multistage compressors.

To these and other ends, which will hereinafter appear, the invention consists of the regulator hereinafter fully described and claimed in this specification and shown in the accompanying drawings, in which Figure 1 is a diagrammatic View partly in longitudinal section and partly broken away, of a two-stage compressor having the regulator applied thereto;

Figure 2 is an enlarged detail side elevation of the regulator partly in vertical sec tion;

Figure 3 is a transverse sectional plan view taken through the central portion of the regulator valve chest on the line 3-3 of Figure 4:;

Figure 4: is a diagrammatic vertical sectional view through the regulator valve chest on the line r-4r. of Figure 3 looking in the 3, 1925. Serial No. 66,493.

direction of the arrows, and assuming that the ports and passages have all been brought into one plane to better illustrate the distribution of the actuating fluid, and

Figure 5 is a detail vertical sectional elevation through the valve chest on the line 55 of Figure 3 looking in the direction of the arrows.

The regulator is applicable to various types of compressors, whether single or inulti-stag-e, but in the present instance I have chosen, for illustrative purposes, to show the regulator applied to a two-stage compound compressor having a low pressure cylinder A and double acting piston B, and a high pressure cylinder C and double acting piston D. The pistons having the piston rods E and F may be driven from any suitable source or sources of power (not shown), and the cylinders are provided with the usual clearance spaces G and H communicating with the cylinders and controlled by suitable normally closed clearance valves T, having the valve casingsl, 2, 3 and 4t mounted on the air heads 0 and P of the cylinder B. The compressor valves Q, for the cylinder A and the compressor valves R for the cylinder B, which may be of the plate type for instance, are mounted in the air heads and serve as inlet or discharge valves in the usual manner. The compressor cylinders are assumed to be connected by suitable piping to each other and to the main receiver tank 8, the piping not being shown for the sake of simplicity.

Each clearance valve T is provided with a stem U having a head V between which and the outer end of the valve casing a com pression spring W is preferably located, tending to close the valve, while the opposite side of the valve head is intermittently subjected to pressure fluid from the receiver 5 for opening the valve. The supply of pressure fluid to the inner faces of the valve heads V successively is controlled by a regulator X forming the subject matter of this invention, actuated by a pressure fluid device, which may be in the form of a diaphragm controlled lever Y movable in accordance with successively attained receiver pressures.

The valve casings 1, 2, 3 and a of the cylinder A are connected respectively to the similarly numbered valve casings, 1, 2, 3 and 4, of the cylinder B by means of the pipes l, 2, ,8 and P, which are in turn connected by branch pipes 1 2", 3 and P to the valve chest Z of the regulator X, so that the clearance valves T are operated in pairs. he

"alve chest Z is provided with a plurality of main valve chambers a conveniently ar ranged around common center, and fluid actuated main regulator valves Z) having the heads 0 and the stems (Z, are longitudinally movable in the valve chambers for controlling the distribution of fluid to and from the valve casings l, 2,3 and hand the movements of the valves T for stepby-step load ing and unloading of the compressor. An auxiliary valve chamber 6 is located centrally in the valve chest Z between the main valve chambers 64, and an auxiliary valve connected to be actuated by the fluid pressure lever Y, is longitudinally movable in the auxiliary valve chamber e for controlling the distribution of fluid to the main valve chambers and the movements of the main regulator valves 6.

The main valve chambers a and auxiliary valve chamber 6 preferably extend through the chest '11 lrom end to end, and the main valve chambers are located in pairs with the chambers of each pair sulliciently close together so that a common inlet passage 9 tending transversely in the valve chest substantially centrally, intersects all of the main valve chambers a at the ports 9 and also the auxiliary valve chamber 6, as indicated diagrammatically in Figure 3 and shown also in Figure 1". This forms a simple construction and reduces the number of parts and passages in the valve chest. 'lhe main inlet passage 1 is suitably co'u-- nected to the pipe 71 leading to the receiver,- by n'lcans ot' the branch pipe The valve chest Z is provided with an end plate 15:, in this instance a l'JOllUlil plate, suitably secured thereto by means of the tap bolts 0, and a cover ,1) secuii'ed over the top ot the valve chest by means of the tap bolts q. The end or bottom plate 7.: is provided with an exl-iaust opening 1' ninunicatiug with the central auxiliary valve chamber 0 and adapted by suitable i orts and passages in the va re chest Z end plate is. controlled by the central. liar valve f, to be placed in i':o1'in'nunic. l J11 succes. el v with one crul of each the ll'itlll'l valve chan'ibers a and with the branch pipes l, 2", and l", leadiirg to pairs ot" clearance valves '1, for releasing the receiver pressure at the forward faces oil the pistons V of said pairs of valves to permit the valves to cl successively under the influence oi the valve springs lV. The coverp is provided with an exhaust passage a, adapted to be placed in communication by suitable ports and passages in the valve chest and cover, successively ith the other ends of the main valve chambers (4. Exhaust pipes 15 and a leading from the exhaust opening '2' and the exhaust passage s rerpectively, may be connected to a common exhaust pipe v open to atn'iosphere.

lleterring more particularly to the construction of the regulator, the valve chest Z may be formed of any suitable material, as for instance bronze, which does not rust and avoids sticking of the valves. A bushing w, also preferably of bronze, terms a lining for the central auxiliary valve chamber e, in which bushing the auxiliary valve f, having the heads 00 and y, is actuated by means of the valve stem passing through the stulling box and pivotally connected to the pressure fluid lever Y at the point (5 by means of the yoke 7. The bushing '70 is provided with central ports 8 and 9 and two of ports 1, 2 3 and l and l, 2, 3 and L, which series of ports are controlled by the auxiliary valve heads 2 and respectively, for admitting pressure to and exhausting pressure from the end pressure surfaces of the auxiliary valves 7), the wrangement of ports and passages in the regulator being such that when pressure is supplied to one end pressure surface of an a"x-ili:'ir};' valve 7) for moving the valve in one direction, the opposite end pressure surface (it the valve is opened to the atmos phere, and vice versa.

The branch pipes l 2, and t" as shown,- con'i municate respectively with the chambers 10 in the valve chest Z, separated from the chambersll by the bridges 12, and the chambers 10 and 11 communicate with the main valve chambers (I by means of the ports 13 and l-l: respectively. Slides l5, carried by the Inain regulator valves 0, control the ports 13 and l4: and these slides may be in the term of shoes held. between the shoulders in on the valve ste ns (Z and prevented from rotating by n'ieans oi the transverse pins 17. The .niain 'alves [I i'n'ay he guided and prevented. from rotating by means of the dowels l8.

(laslwts 19, ot any siiitable material as rubber or fiber, are prclferably placed bi tween the valve chest Z and the end plate it" and co er 1), and properly perforated to cont rm to the ports and passages in the parts of the regulator. The material. of the gaskets preferably over-laps the main regulator valve chambers a, at the points 2'0 in order lo form a cushion and a seal for the main regulator valves against wh ch over lapping portions ot the gaskets the valve heads impinge on their operation. Removable plugs 21 closing the apertures 22 in the cover 79, in axial alignment with the main regulator valves, alliord accessibility to the interior of the regulator and permit oilin The lluid pressure lever Y which actuates the central auxiliary valve 7 may be of any suitable form or construction, but in this instance is in the form of an arm pivoted at 23 to the frame or support 24, carrying adjustahle weights 25 at its outer end. The lever rests on the upper end of a pin 26 supported in the guide 27, carried by the diaphragm 28 which is subjected to receiver pressure from the receiver S through the pipe h. A given increase of pressure in the receiver will expand the diaphragm 28 and carry the lever Y upwardly, thus moving the auxiliary regulator or valve f upwardly a given distance. A coiled spring 29, supported between the regulator frame 30 and the cap 'll pinned to the rod 32, which is pivotel to the lever Y at the point 33, re sists the upward movement of the lever Y. A stop 34; on the rod limits the downward movement of the lever.

in the operation of the apparatus let it be assun'ied that the compressor has been operating with all the clearance valves T closed, and held in, closed position by the springs behind the heads V oi the valves. The lever Y would then. be at the limit of its downward movement and all the main regulator valves would he in their upard position, as Figure 4t is viewed, that is they would all be in the position of the main regulator valve 7) at the right of said ligure, and the auxiliary regulator valve f would be at the limit of its downward travel.

In such case, the respective valve casings ot the clearance valves T on both cylinders are open to atmosphere through the pipes l", 2*, 3" and 4t" and the remaining pipes connected thereto, since the pairs of chambers and 11 in the regulator casing are placed in communication by the slides 15, and the chambers 11 are open to atmosphere through ports 50, coimnon passage 5l in the end plate is and atmospheric pipes t and '0. The clearance valves are thus all held closed by their springs.

The main regulator valves I) would all be held in upward position, as Figure 4 is viewed. due to receiver pressure from the main inlet passage f/ through the respective series of ports 1", 2", 3", and t, thence through the chamhers B l, ports 2-35 and 3t), and passages $17. and lo the end pressure surfaces ol the main regulator valve heads 0, tending to hold the valves upward. The opposite end pressure suril accs of the main regulator valves on the opposite heads 0 are opened to exhaust through the passages 38, ports i3!) and ll), chan'ibers ill and the series of ports l. 5 3, 3 and l and thence around the auxiliary regulator valve directly to the 8X- haust passage 8.

Let it then be assumed that there is a sutlicient increase of receiver pressure heneath the diaphragm 53% ot the lever Y to raise the lever and the auxiliary valve the first step to the position of the auxiliary valve 7 indicated in Figure 4, so that the auxiliary valve heads y and have uncovered the ports 1 and 1 The lower end pressure surface of one main regulator valve l: controlling the branch pipe 1 leading to the clearance valves 1 in the valve casings 1 will he exhausted to atmosphere through the exhaustpipe t. Receiver pressure is also admitted to the opposite end pressure surface or" the said main regulator valve 7) from the main inlet pipe through the port 1% chamber 4E1, ports 4-0 and 39, and pass go 38. to the main valve chamber a tor said valve. The valve will be thrown to its opposite position and the slide places the ports 13 in communication with the pressure fluid pipe {7. which supplies the receiver pressure to the heads V of the clearance valves T in the 'alve casings 1, through the pipes l and l and thus opening the said clearance valves to unload the compressor the desired degree.

At successively attained receiver pressures, the pairs ol clearance valves are successively opened as the auxiliary regulator valve continues to uncover pairs of ports in the two series of ports 1 2 3 and a and l, 2, 3 and i. The pairs of clearance valves are successively closed. automatically as the auxiliary regulator valve f is moved in the opposite direction.

I am not to he understood as limiting the invention to the details of construction shown and described since those skilled in the art may devise equivalent constructions for carrying out my invention, as defined in the appended claims.

The regulator disclosed is structurally designed so that the receiver pressure may be e'lllciently applied for positively opening the clearance valves. Each main valve F) has a definite function to perform and controls the supply of receiver pressure to actuate the clearance valves in an opening direction. This construction is also advantageous in case some or all of the unloading steps are efi'ected by holding open one or more of the inlet valves as in the so-callcd free air unloading system.

l claim:

I. In. a compressor Imloadcr, the combination ol' a compro:=.-tsor cylinder and piston, a receiver, a nearanco chamber for the cylinder, a normally closed clearance valve having a cylinder and piston, a regulator having a valve chest, a controlling valve in said valve chest automatirnilly responsive to receiver pressure, a fluid connection between said valve chest and the t'orward face of the piston in the cylinder of said clearance valve, and ports and passages in said regulater for controlling the supply and release of receiver pressure in said fluid connection to the clearance valve piston, whereby the clearance valve is positively and automatically opened by receiver pressure and closed by release of said pressure.

2. In a compressor unloader, the combination of a compressor c 'linder and piston, a receiver, a clearance chamber for the cylinder, a norn'ially closed clearance valve having acylindcr and piston, a regulator having a valve chest, an auxiliary controlling valve in said valve chest, automatically responsive to receiv r pressure, a main regulator valve in said regulator, a fluid connec tion between said main regulator valve and the forward face of the piston in the cylinder of said clearance valve, and ports and passages in said regulator for controlling the main regulator valve and thereby conrolling the supply and release of receiver pressure in said connection to the clearance valve piston, whereby the clearance valve is positively and automatically opened by receiver pressure and closed by release of said pressure.

3V in a compressor unloader, the combination of a cylinder and piston, a receiver, a clearance chamber for the cylinder, a norn'ially closed clearance valve having a cylinder and piston, a regulator having a controlling; valve automatically responsive to receiver pressure, a pressure fluid connection between said regulator and the forward face of the piston in the cylinder of the clearance valve, and ports and passages in said regulator i'or controlling; the supply and ielease of receiver pressure in said pressure liuid connection to the clearance valve piston, whereby the clearance valve is positively and automatically opened by receiver pressure and closed by release of said pressure.

in testimony whereof I have signed this specification.

CHESTER W. METZGAR. 

